Imaging lens, and electronic apparatus including the same

ABSTRACT

An imaging lens includes first to sixth lens elements arranged from an object side to an image side in the given order. Through designs of surfaces of the lens elements and relevant optical parameters, a larger field of view and a shorter system length of the imaging lens may be achieved while maintaining good optical performance.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Chinese Application No.201410234542.5, filed on May 29, 2014.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an imaging lens and an electronicapparatus including the same.

2. Description of the Related Art

In recent years, as use of portable electronic devices (e.g., mobilephones and digital cameras) becomes ubiquitous, much effort has been putinto reducing dimensions of portable electronic devices. Moreover, asdimensions of charged coupled device (CCD) and complementary metal-oxidesemiconductor (CMOS) based optical sensors are reduced, dimensions ofimaging lenses for use with the optical sensors must be correspondinglyreduced without significantly compromising optical performance.

U.S. Pat. No. 8,385,006 discloses a conventional imaging lens thatincludes first, second, third, fourth fifth and sixth lens elements. Thefirst lens element has a positive refractive power and the third lenselement has a negative refractive power. Such structure results in arelatively small field of view of the conventional imaging lens, anddoes not meet current demands of a larger field of view.

Therefore, it is required to develop a miniaturized optical imaging lenshaving an increased field of view, reduced dimensions, and good imagingquality that may satisfy requirements of consumer electronic products.

SUMMARY OF THE INVENTION

Therefore, an object of the present invention is to provide an imaginglens having a relatively large field of view while maintaining goodoptical performance.

According to one aspect of the present invention, an imaging lenscomprises a first lens element, a second lens element, a third lenselement, a fourth lens element, a fifth lens element and a sixth lenselement arranged in order from an object side to an image side along anoptical axis of the imaging lens. Each of the first lens element, thesecond lens element, the third lens element, the fourth lens element,the fifth lens element and the sixth lens element has a refractivepower, an object-side surface facing toward the object side and animage-side surface facing toward the image side.

The first lens element has a negative refractive power. The object-sidesurface of the first lens element is a convex surface that has a convexportion in a vicinity of the optical axis and a convex portion in avicinity of the periphery. The image-side surface of the second lenselement has a convex portion in a vicinity of a periphery of the secondlens element. The third lens element has a positive refractive power andthe image-side surface of the third lens element has a convex portion ina vicinity of a periphery of the third lens element. The object-sidesurface of the fourth lens element has a concave portion in a vicinityof a periphery of the fourth lens element. The object-side surface ofthe fifth lens element has a concave portion in a vicinity of aperiphery of the fifth lens element. The image-side surface of the sixthlens element has a concave portion in a vicinity of the optical axis anda convex portion in a vicinity of a periphery of the sixth lens element.The imaging lens does not include any lens element with refractive powerother than the aforesaid lens elements 3-8.

Another object of the present invention is to provide an electronicapparatus having an imaging lens with six lens elements.

According to another aspect of the present invention, an electronicapparatus includes a housing and an imaging module. The imaging moduleis disposed in the housing, and includes the imaging lens of the presentinvention, a barrel on which the imaging lens is disposed, a holder uniton which the barrel is disposed, and an image sensor disposed at theimage side of the imaging lens.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of the present invention will becomeapparent in the following detailed description of the preferredembodiments with reference to the accompanying drawings, of which:

FIG. 1 is a schematic diagram to illustrate the structure of a lenselement;

FIG. 2 is a schematic diagram that illustrates the first preferredembodiment of an imaging lens according to the present invention;

FIG. 3 shows values of some optical parameters corresponding to theimaging lens of the first preferred embodiment;

FIG. 4 shows values of some parameters of an optical relationshipcorresponding to the imaging lens of the first preferred embodiment;

FIGS. 5(a) to 5(d) show different optical characteristics of the imaginglens of the first preferred embodiment;

FIG. 6 is a schematic diagram that illustrates the second preferredembodiment of an imaging lens according to the present invention;

FIG. 7 shows values of some optical parameters corresponding to theimaging lens of the second preferred embodiment;

FIG. 8 shows values of some parameters of an optical relationshipcorresponding to the imaging lens of the second preferred embodiment;

FIGS. 9(a) to 9(d) show different optical characteristics of the imaginglens of the second preferred embodiment;

FIG. 10 is a schematic diagram that illustrates the third preferredembodiment of an imaging lens according to the present invention;

FIG. 11 shows values of some optical parameters corresponding to theimaging lens of the third preferred embodiment;

FIG. 12 shows values of some parameters of an optical relationshipcorresponding to the imaging lens of the third preferred embodiment;

FIGS. 13(a) to 13(d) show different optical characteristics of theimaging lens of the third preferred embodiment;

FIG. 14 is a schematic diagram that illustrates the fourth preferredembodiment of an imaging lens according to the present invention;

FIG. 15 shows values of some optical parameters corresponding to theimaging lens of the fourth preferred embodiment;

FIG. 16 shows values of some parameters of an optical relationshipcorresponding to the imaging lens of the fourth preferred embodiment;

FIGS. 17(a) to 17(d) show different optical characteristics of theimaging lens of the fourth preferred embodiment;

FIG. 18 is a schematic diagram that illustrates the fifth preferredembodiment of an imaging lens according to the present invention;

FIG. 19 shows values of some optical parameters corresponding to theimaging lens of the fifth preferred embodiment;

FIG. 20 shows values of some parameters of an optical relationshipcorresponding to the imaging lens of the fifth preferred embodiment;

FIGS. 21(a) to 21(d) show different optical characteristics of theimaging lens of the fifth preferred embodiment;

FIG. 22 is a schematic diagram that illustrates the sixth preferredembodiment of an imaging lens according to the present invention;

FIG. 23 shows values of some optical parameters corresponding to theimaging lens of the sixth preferred embodiment;

FIG. 24 shows values of some parameters of an optical relationshipcorresponding to the imaging lens of the sixth preferred embodiment;

FIGS. 25(a) to 25(d) show different optical characteristics of theimaging lens of the sixth preferred embodiment;

FIG. 26 is a schematic diagram that illustrates the seventh preferredembodiment of an imaging lens according to the present invention;

FIG. 27 shows values of some optical parameters corresponding to theimaging lens of the seventh preferred embodiment;

FIG. 28 shows values of some parameters of an optical relationshipcorresponding to the imaging lens of the seventh preferred embodiment;

FIGS. 29(a) to 29(d) show different optical characteristics of theimaging lens of the seventh preferred embodiment;

FIG. 30 is a schematic diagram that illustrates the eighth preferredembodiment of an imaging lens according to the present invention;

FIG. 31 shows values of some optical parameters corresponding to theimaging lens of the eighth preferred embodiment;

FIG. 32 shows values of some parameters of an optical relationshipcorresponding to the imaging lens of the eighth preferred embodiment;

FIGS. 33(a) to 33(d) show different optical characteristics of theimaging lens of the eighth preferred embodiment;

FIGS. 34 and 35 are tables each listing values of parameters of otheroptical relationships corresponding to the imaging lenses of the firstto eighth preferred embodiments;

FIG. 36 is a schematic partly sectional view to illustrate a firstexemplary application of the imaging lens of the present invention; and

FIG. 37 is a schematic partly sectional view to illustrate a secondexemplary application of the imaging lens of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Before the present invention is described in greater detail, it shouldbe noted that like elements are denoted by the same reference numeralsthroughout the disclosure.

In the following description, “a lens element has a positive (ornegative) refractive power” means the lens element has a positive (ornegative) refractive power in a vicinity of an optical axis thereof. “Anobject-side surface (or image-side surface) has a convex (or concave)portion at a certain area” means that, compared to a radially exteriorarea adjacent to said certain area, said certain area is more convex (orconcave) in a direction parallel to the optical axis. Referring to FIG.1 as an example, the lens element is radially symmetrical with respectto an optical axis (I) thereof. The object-side surface of the lenselement has a convex portion at an area A, a concave portion at an areaB, and a convex portion at an area C. This is because the area A is moreconvex in a direction parallel to the optical axis (I) in comparisonwith a radially exterior area thereof (i.e., area B), the area B is moreconcave in comparison with the area C, and the area C is more convex incomparison with an area E. “In a vicinity of a periphery” refers to anarea around a periphery of a curved surface of the lens element forpassage of imaging light only, which is the area C in FIG. 1. Theimaging light includes a chief ray Lc and a marginal ray Lm. “In avicinity of the optical axis” refers to an area around the optical axisof the curved surface for passage of the imaging light only, which isthe area A in FIG. 1. In addition, the lens element further includes anextending portion E for installation into an optical imaging lensdevice. Ideally, the imaging light does not pass through the extendingportion E. The structure and shape of the extending portion E are notlimited herein. In the following embodiments, the extending portion E isnot depicted in the drawings for the sake of clarity.

Referring to FIG. 2, the first preferred embodiment of an imaging lens10 according to the present invention includes a first lens element 3, asecond lens element 4, an aperture stop 2, a third lens element 5, afourth lens element 6, a fifth lens elements 7, a sixth lens element 8and an optical filter 9 arranged in the given order along an opticalaxis (I) from an object side to an image side. The optical filter 9 isan infrared cut filter for selectively absorbing infrared light tothereby reduce imperfection of images formed at an image plane 100.

Each of the first, second, third, fourth, fifth and sixth lens elements3-8 and the optical filter 9 has an object-side surface 31, 41, 51, 61,71, 81, 91 facing toward the object side, and an image-side surface 32,42, 52, 62, 72, 82, 92 facing toward the image side. Light entering theimaging lens 10 travels through the object-side and image-side surfaces31, 32 of the first lens element 3, the object-side and image-sidesurfaces 41, 42 of the second lens element 4, the aperture stop 2, theobject-side and image-side surfaces 51, 52 of the third lens element 5,the object-side and image-side surfaces 61, 62 of the fourth lenselement 6, the object-side and image-side surfaces 71, 72 of the fifthlens element 7, the object-side and image-side surfaces 81, 82 of thesixth lens element 8, and the object-side and image-side surfaces 91, 92of the optical filter 9, in the given order, to form an image on theimage plane 100. Each of the object-side surfaces 41, 51, 61, 71, 81 andthe image-side surfaces 32, 42, 52, 62, 72, 82 is aspherical and has acenter point coinciding with the optical axis (I).

The lens elements 3-8 are made of a plastic material in this embodimentsuch that weight and cost of the imaging lens 10 may be reduced. Itshould be noted that the lens elements 3-8 may be made of othermaterials in other embodiments.

In the first preferred embodiment, which is depicted in FIG. 2, thefirst lens element 3 has a negative refractive power. The object-sidesurface 31 of the first lens element 3 is a convex surface that has aconvex portion 311 in a vicinity of the optical axis (I) and a convexportion 312 in a vicinity of a periphery of the first lens element 3.The image-side surface 32 of the first lens element 3 is a concavesurface that has a concave portion 321 in a vicinity of the optical axis(I) and a concave portion 322 in a vicinity of the periphery of thefirst lens element 3.

The second lens element 4 has a positive refractive power. Theobject-side surface 41 of the second lens element 4 is a concave surfacethat has a concave portion 411 in a vicinity of the optical axis (I),and a concave portion 412 in a vicinity of a periphery of the secondlens element 4. The image-side surface 42 of the second lens element 4is a convex surface that has a convex portion 421 in a vicinity of theoptical axis (I), and a convex portion 422 in a vicinity of theperiphery of the second lens element 4.

The third lens element 5 has a positive refractive power. Theobject-side surface 51 of the third lens element 5 is a convex surfacethat has a convex portion 511 in a vicinity of the optical axis (I), anda convex portion 512 in a vicinity of a periphery of the third lenselement 5. The image-side surface 52 of the third lens element 5 is aconvex surface that has a convex portion 521 in a vicinity of theoptical axis (I), and a convex portion 522 in a vicinity of theperiphery of the third lens element 5.

The fourth lens element 6 has a negative refractive power. Theobject-side surface 61 of the fourth lens element 6 is a concave surfacethat has a concave portion 611 in a vicinity of the optical axis (I),and a concave portion 612 in a vicinity of a periphery of the fourthlens element 6. The image-side surface 62 of the fourth lens element 6has a concave portion 621 in a vicinity of the optical axis (I), and aconvex portion 622 in a vicinity of the periphery of the fourth lenselement 6.

The fifth lens element 7 has a positive refractive power. Theobject-side surface 71 of the fifth lens element 7 has a convex portion711 in a vicinity of the optical axis (I), and a concave portion 712 ina vicinity of a periphery of the fifth lens element 7. The image-sidesurface 72 of the fifth lens element 7 has a concave portion 721 in avicinity of the optical axis (I), and a convex portion 722 in a vicinityof the periphery of the fifth lens element 7.

The sixth lens element 8 has a negative refractive power. Theobject-side surface 81 of the sixth lens element 8 is a convex surfacethat has a convex portion 311 in a vicinity of the optical axis (I) anda convex portion 812 in a vicinity of a periphery of the sixth lenselement 8. The image-side surface 82 of the sixth lens element 8 has aconcave portion 821 in a vicinity of the optical axis (I) and a convexportion 822 in a vicinity of a periphery of the sixth lens element 8.

In the first preferred embodiment, the imaging lens 10 does not includeany lens element with refractive power other than the aforesaid lenselements 3-8.

Shown in FIG. 3 is a table that lists values of some optical parameterscorresponding to the surfaces 31-91, 32-92 of the first preferredembodiment. The imaging lens 10 has an overall system effective focallength (EFL) of 2.037 mm, a half field-of-view (HFOV) of 70.00°, anF-number of 2.2, and a system length of 3.6309 mm. The system lengthrefers to a distance between the object-side surface 31 of the firstlens element 3 and the image plane 100 at the optical axis (I).

In this embodiment, each of the object-side surfaces 41-81 and theimage-side surfaces 32-82 is aspherical, and satisfies the opticalrelationship of

$\begin{matrix}{{Z(Y)} = {{\frac{Y^{2}}{R}/\left( {1 + \sqrt{1 - {\left( {1 + K} \right)\frac{Y^{2}}{R^{2}}}}} \right)} + {\sum\limits_{i = 1}^{n}\;{a_{2i} \times Y^{2t}}}}} & (1)\end{matrix}$

where:

Y represents a perpendicular distance between an arbitrary point on anaspherical surface and the optical axis (I);

Z represents a depth of the aspherical surface, which is defined as aperpendicular distance between the arbitrary point on the asphericalsurface that is spaced apart from the optical axis (I) by a distance Y,and a tangent plane at a vertex of the aspherical surface at the opticalaxis (I);

R represents a radius of curvature of the aspherical surface;

K represents a conic constant; and

a_(2i) represents a 2i^(th) aspherical coefficient.

Shown in FIG. 4 is a table that lists values of some optical parametersof the aforementioned optical relationship (1) corresponding to thefirst preferred embodiment. Note that in FIG. 4, the column under “32”represents aspherical coefficients of the image-side surface 32 of thefirst lens element 3 and the values listed in the other columnscorrespond to other surfaces of the lens elements 4-8.

Relationships among some of the aforementioned optical parameterscorresponding to the first preferred embodiment are shown in FIG. 34,where:

T1 represents a thickness of the first lens element 3 at the opticalaxis (I);

T2 represents a thickness of the second lens element 4 at the opticalaxis (I);

T3 represents a thickness of the third lens element 5 at the opticalaxis (I);

T4 represents a thickness of the fourth lens element 6 at the opticalaxis (I);

T5 represents a thickness of the fifth lens element 7 at the opticalaxis (I);

T6 represents a thickness of the sixth lens element 8 at the opticalaxis (I);

G12 represents an air gap width between the first lens element 3 and thesecond lens element 4 at the optical axis (I);

G23 represents an air gap width between the second lens element 4 andthe third lens element 5 at the optical axis (I);

G34 represents an air gap width between the third lens element 5 and thefourth lens element 6 at the optical axis (I);

G45 represents an air gap width between the fourth lens element 6 andthe fifth lens element 7 at the optical axis (I);

G56 represents an air gap width between the fifth lens element 7 and thesixth lens element 8 at the optical axis (I);

Gaa represents a sum of air gap widths among the first lens element 3,the second lens element 4, the third lens element 5, the fourth lenselement 6, the fifth lens element 7, and the sixth lens element 8 at theoptical axis (I), i.e., a sum of G12, G23, G34, G45 and G56;

ALT represents a sum of the thicknesses of the first lens element 3, thesecond lens element 4, the third lens element 5, the fourth lens element6, the fifth lens element 7 and the sixth lens element 8 at the opticalaxis (I), i.e., a sum of T1, T2, T3, T4, T5 and T6;

TTL represents a distance at the optical axis (I) between theobject-side surface 31 of the first lens element 3 and the image plane100 at the image side; and

BFL represents a distance at the optical axis (I) between the image-sidesurface 82 of the sixth lens element 8 and the image plane 100.

FIGS. 5(a) to 5(d) respectively show simulation results corresponding tolongitudinal spherical aberration, sagittal astigmatism aberration,tangential astigmatism aberration, and distortion aberration of thefirst preferred embodiment. In each of the simulation results, curvescorresponding respectively to wavelengths of 470 nm, 555 nm, and 650 nmare shown.

It can be understood from FIG. 5(a) that, since each of the curvescorresponding to longitudinal spherical aberration has a focal length ateach field of view (indicated by the vertical axis) that falls withinthe range of ±0.01 mm, the first preferred embodiment is able to achievea relatively low spherical aberration at each of the wavelengths.Furthermore, since the curves at each field of view are close to eachother, the first preferred embodiment has a relatively low chromaticaberration.

It can be understood from FIGS. 5(b) and 5(c) that, since each of thecurves falls within the range of ±0.1 mm of focal length, the firstpreferred embodiment has a relatively low optical aberration.

Moreover, as shown in FIG. 5(d), since each of the curves correspondingto distortion aberration falls within the range of ±70%, the firstpreferred embodiment is able to meet requirements in imaging quality ofmost optical systems.

In view of the above, even with the system length reduced down to 3.6mm, the imaging lens 10 of the first preferred embodiment is still ableto achieve a relatively good optical performance.

It should be noted that the reference numerals of the concave portionsand the convex portions in the following embodiments that are the sameas those in the first embodiment are omitted in the drawings for thesake of brevity.

Referring to FIG. 6, the differences between the first and secondpreferred embodiments of the imaging lens 10 of this invention reside inmodifications of some optical data, aspherical coefficients and the lensparameters of the lens elements 3-8.

Shown in FIG. 7 is a table that lists values of some optical parameterscorresponding to the surfaces 31-91, 32-92 of the second preferredembodiment. The imaging lens 10 has an overall system focal length of2.031 mm, an HFOV of 70.00°, an F-number of 2.2, and a system length of3.6041 mm.

Shown in FIG. 8 is a table that lists values of some optical parametersof the aforementioned optical relationship (1) corresponding to thesecond preferred embodiment.

Relationships among some of the aforementioned optical parameterscorresponding to the second preferred embodiment are shown in FIG. 34.

FIGS. 9(a) to 9(d) respectively show simulation results corresponding tolongitudinal spherical aberration, sagittal astigmatism aberration,tangential astigmatism aberration, and distortion aberration of thesecond preferred embodiment. It can be understood from FIGS. 9(a) to9(d) that the second preferred embodiment is able to achieve arelatively good optical performance.

Referring to FIG. 10, the first and third preferred embodiments aresimilar except for some optical data, aspherical coefficients and thelens parameters of the lens elements 3-3. In this embodiment, theimage-side surface 72 of the fifth lens element 7 is a concave surfacethat has a concave portion 723 in a vicinity of the periphery of thefifth lens element 7.

Shown in FIG. 11 is a table that lists values of some optical parameterscorresponding to the surfaces 31-91, 32-92 of the third preferredembodiment. The imaging lens 10 has an overall system focal length of2.036 mm, an HFOV of 70.00°, an F-number of 2.2, and a system length of3.8118 mm.

Shown in FIG. 12 is a table that lists values of some optical parametersof the aforementioned optical relationship (1) corresponding to thethird preferred embodiment.

Relationships among some of the aforementioned optical parameterscorresponding to the third preferred embodiment are shown in FIG. 34.

FIGS. 13(a) to 13(d) respectively show simulation results correspondingto longitudinal spherical aberration, sagittal astigmatism aberration,tangential astigmatism aberration, and distortion aberration of thethird preferred embodiment. It can be understood from FIGS. 13(a) to13(d) that the third preferred embodiment is able to achieve arelatively good optical performance.

Referring to FIG. 14, the fourth preferred embodiment is similar to thefirst preferred embodiment except for some optical data, asphericalcoefficients and the lens parameters of the lens elements 3-8.

Shown in FIG. 15 is a table that lists values of some optical parameterscorresponding to the surfaces 31-91, 32-92 of the fourth preferredembodiment. The imaging lens 10 has an overall system focal length of1.983 mm, an HFOV of 70.00°, an F-number of 2.2, and a system length of4.8654 mm.

Shown in FIG. 1.6 is a table that lists values of some opticalparameters of the aforementioned optical relationship (1) correspondingto the fourth preferred embodiment.

Relationships among some of the aforementioned optical parameterscorresponding to the fourth preferred embodiment are shown in FIG. 34.

FIGS. 17(a) to 17(d) respectively show simulation results correspondingto longitudinal spherical aberration, sagittal astigmatism aberration,tangential astigmatism aberration, and distortion aberration of thefourth preferred embodiment. It can be understood from FIGS. 17(a) to17(d) that the fourth preferred embodiment is able to achieve arelatively good optical performance.

Referring to FIG. 18, the first and fifth preferred embodiments aresimilar except for some optical data, aspherical coefficients and thelens parameters of the lens elements 3-8.

Shown in FIG. 19 is a table that lists values of some optical parameterscorresponding to the surfaces 31-91, 32-92 of the fifth preferredembodiment. The imaging lens 10 has an overall system focal length of1.917 mm, an HFOV of 70.00°, an F-number of 2.2, and a system length of3.4691 mm.

Shown in FIG. 20 is a table that lists values of some optical parametersof the aforementioned optical relationship (1) corresponding to thefifth preferred embodiment.

Relationships among some of the aforementioned optical parameterscorresponding to the fifth preferred embodiment are shown in FIG. 35.

FIGS. 21(a) to 21(d) respectively show simulation results correspondingto longitudinal spherical aberration, sagittal astigmatism aberration,tangential astigmatism aberration, and distortion aberration of thefifth preferred embodiment. It can be understood from FIGS. 21(a) to21(d) that the fifth preferred embodiment is able to achieve arelatively good optical performance.

FIG. 22 illustrates the sixth preferred embodiment of an imaging lens 10according to the present invention, which has a configuration similar tothat of the first preferred embodiment except for some optical data,aspherical coefficients and the lens parameters of the lens elements3-8. The differences between the first and sixth preferred embodimentsreside in that, in this embodiment, the image-side surface 72 of thefifth lens element 7 is a concave surface that has a concave portion 723in a vicinity of the periphery of the fifth lens element 7. Theobject-side surface 81 of the sixth lens element 8 has a concave portion813 in a vicinity of the periphery of the sixth lens element 8.

Shown in FIG. 23 is a table that lists values of some optical parameterscorresponding to the surfaces 31-91, 32-92 of the sixth preferredembodiment. The imaging lens 10 has an overall system focal length of1.814 mm, an HFOV of 70.00°, an F-number of 2.2, and a system length of3.2264 mm.

Shown in FIG. 24 is a table that lists values of some optical parametersof the aforementioned optical relationship (1) corresponding to thesixth preferred embodiment.

Relationships among some of the aforementioned optical parameterscorresponding to the sixth preferred embodiment are shown in FIG. 35.

FIGS. 25(a) to 25(d) respectively show simulation results correspondingto longitudinal spherical aberration, sagittal astigmatism aberration,tangential astigmatism aberration, and distortion aberration of thesixth preferred embodiment. It can be understood from FIGS. 25(a) to25(d) that the sixth preferred embodiment is able to achieve arelatively good optical performance.

Referring to FIG. 26, a seventh preferred embodiment of the imaging lens10 according to the present invention is similar to the first preferredembodiment except for some optical data, aspherical coefficients and thelens parameters of the lens elements 3-8. The differences between thefirst and seventh preferred embodiments of the imaging lens 10 of thisinvention reside in that: the second lens element 4 has a negativerefractive power and the object-side surface 41 of the second lenselement 4 has a convex portion 413 in a vicinity of the optical axis(I). The image-side surface 42 of the second lens element 4 has aconcave portion 423 in a vicinity of the optical axis (I). Theobject-side surface 61 of the fourth lens element 6 has a convex portion613 in a vicinity of the optical axis (I). The sixth lens element 8 hasa positive refractive power. The object-side surface 81 of the sixthlens element 8 has a concave portion 813 in a vicinity of the peripheryof the sixth lens element 8.

Shown in FIG. 27 is a table that lists values of some optical parameterscorresponding to the surfaces 31-91, 32-92 of the seventh preferredembodiment. The imaging lens 10 has an overall system focal length of2.112 mm, an HFOV of 60.00°, an F-number of 2.4, and a system length of6.0468 mm.

Shown in FIG. 28 is a table that lists values of some optical parametersof the aforementioned optical relationship (1) corresponding to theseventh preferred embodiment.

Relationships among some of the aforementioned optical parameterscorresponding to the seventh preferred embodiment are shown in FIG. 35.

FIGS. 29(a) to 29(d) respectively show simulation results correspondingto longitudinal spherical aberration, sagittal astigmatism aberration,tangential astigmatism aberration, and distortion aberration of theseventh preferred embodiment. It can be understood from FIGS. 29(a) to29(d) that the seventh preferred embodiment is able to achieve arelatively good optical performance.

Referring to FIG. 30, the differences between the first and eighthpreferred embodiments of the imaging lens 10 of this invention reside inmodifications of some optical data, aspherical coefficients and the lensparameters of the lens elements 3-8. Moreover, the object-side surface81 of the sixth lens element 8 has a concave portion 813 in a vicinityof the periphery of the sixth lens element 8.

Shown in FIG. 31 is a table that lists values of some optical parameterscorresponding to the surfaces 31-91, 32-92 of the eighth preferredembodiment. The imaging lens 10 has an overall system focal length of2.008 mm, an HFOV of 70.00°, an F-number of 2.2, and a system length of3.7307 mm.

Shown in FIG. 32 is a table that lists values of some optical parametersof the aforementioned optical relationship (1) corresponding to theeighth preferred embodiment.

Relationships among some of the aforementioned optical parameterscorresponding to the eighth preferred embodiment are shown in FIG. 35.

FIGS. 33(a) to 33(d) respectively show simulation results correspondingto longitudinal spherical aberration, sagittal astigmatism aberration,tangential astigmatism aberration, and distortion aberration of theeighth preferred embodiment. It can be understood from FIGS. 33(a) to33(d) that the eighth preferred embodiment is able to achieve arelatively good optical performance.

Shown in FIGS. 34 and 35 are tables that list relationships among someof the aforementioned optical parameters corresponding to the eightpreferred embodiments for comparison. When each of the opticalparameters of the imaging lens 10 according to this invention satisfiesthe following optical relationships, the system length may be reducedwhile maintaining good optical performance:

1. Gaa/T5≧1.25; T6/T3≦1.5; T6/G12≦7.0; T6/T1≦2.6; ALT/T5≧5.0; T5/T1≦2.1;T5/(G45+G56)≦2.7; and T5/T3≦1.05. Since reducing T5 and T6 may reduceoptical aberration of the imaging lens 10, the designs of Gaa/T5 andALT/T5 should tend to be large whereas the designs of T6/T3, T6/G12,T6/T1, T5/T1, T5/(G45+G56), and T5/T3 should tend to be small. Betterarrangement may be achieved when these relationships are satisfied.Preferably, 1.25≦Gaa/T5≦5.0; 0.4≦T6/T3≦1.5; 0.8≦T6/G12≦7.0;0.6≦T6/T1≦2.6; 5.0≦ALT/T5≦15.0; 0.2≦T5/T1≦2.1; 0.3≦T5/(G45+G56)≦2.7; and0.3≦T5/T3≦1.05.

2. ALT/G12≦30; (G23+G34)/G12≦4.8; and (G34+G56)/G12≦5.0. the lenselements 3 and 4 should be wide enough to facilitate increasing in fieldof view of the imaging lens 10. The designs of ALT, G23, G34 and G56should tend to be small for facilitating reduction of the system lengthof the imaging lens 10. Better arrangement may be achieved when theserelationships are satisfied. Preferably, 5.0≦ALT/G12≦30.0;0.4≦(G23+G34)/G12≦4.8; and 0.6≦(G34+G56)/G12≦5.0.

3. T3/T4≧1.7; (G23+G34)/T4≦1.5; T2/(G45+G56)≦3.0; and Gaa/(G23+G34)≧2.0.Ratios among T2, T3, T4, G23, G34, G45, G56, and Gaa should be proper toavoid any one of these parameters being too large, resulting in a longsystem length of the imaging lens 10, and/or to avoid any one of theseparameters being too small, resulting in difficulty in manufacturing theimaging lens 10. Better arrangement may be achieved when theserelationships are satisfied. Preferably, 1.7≦T3/T4≦3.0;1.4≦(G23+G34)/T4≦1.5; 0.7≦T2/(G45+G56)≦3.0; and 2.0≦Gaa/(G23+G34)≦5.0.

To sum up, effects and advantages of the imaging lens 10 according tothe present invention are described hereinafter.

1. The design of the first lens element 3 that has a negative refractivepower increases field of view of the imaging lens 10 and the design ofthe third lens element 5 that has a positive refractive power providessufficient refractive power to the imaging lens 10. Further, by virtueof the convex portion 311 and the convex portion 312 that collect lightfor imaging, the convex portion 422, the convex portion 522, the concaveportion 612, the concave portion 712, the concave portion 821, and theconvex portion 822, optical aberration may be corrected, therebyensuring imaging quality of the imaging lens 10.

2. Through design of the relevant optical parameters, opticalaberrations, such as spherical aberration, may be reduced or eveneliminated. Further, through surface design and arrangement of the lenselements 3-8, even with the reduced system length, optical aberrationsmay still be reduced or even eliminated, resulting in relatively goodoptical performance.

3. Through the aforesaid eight preferred embodiments, it is known thatthe system length of this invention may be reduced down to below 6.1 mm,so as to facilitate developing thinner relevant products with economicbenefits.

Shown in FIG. 36 is a first exemplary application of the imaging lens 10of this invention, in which the imaging lens 10 is disposed in a housing11 of an electronic apparatus 1 (such as a mobile phone, but not limitedthereto), and forms a part of an imaging module 12 of the electronicapparatus 1. The imaging module 12 includes a barrel 21 on which theimaging lens 10 is disposed, a holder unit 120 on which the barrel 21 isdisposed, and an image sensor 130 disposed at the image plane 100 (seeFIG. 2).

The holder unit 120 includes a first holder portion 121 in which thebarrel 21 is disposed, and a second holder portion 122 having a portioninterposed between the first holder portion 121 and the image sensor130. The barrel 21 and the first holder portion 121 of the holder unit120 extend along an axis (II), which coincides with the optical axis (I)of the imaging lens 10.

Shown in FIG. 37 is a second exemplary application of the imaging lens10 of this invention. The differences between the first and secondexemplary applications reside in that, in the second exemplaryapplication, the holder unit 120 is configured as a voice-coil motor(VCM), and the first holder portion 121 includes an inner section 123 inwhich the barrel 21 is disposed, an outer section 124 that surrounds theinner section 123, a coil 125 that is interposed between the inner andouter sections 123, 124, and a magnetic component 126 that is disposedbetween an outer side of the coil 125 and an inner side of the outersection 124.

The inner section 123 and the barrel 21, together with the imaging lens10 therein, are movable with respect to the image sensor 130 along anaxis (III), which coincides with the optical axis (1) of the imaginglens 10. The optical filter 9 of the imaging lens 10 disposed at thesecond holder portion 122, which is disposed to abut against the outersection 124. Configuration and arrangement of other components of theelectronic apparatus 1 in the second exemplary application are identicalto those in the first exemplary application, and hence will not bedescribed hereinafter for the sake of brevity.

By virtue of the imaging lens 10 of the present invention, theelectronic apparatus 1 in each of the exemplary applications may beconfigured to have a relatively reduced overall thickness with goodoptical and imaging performance, so as to reduce cost of materials, andsatisfy requirements of product miniaturization.

While the present invention has been described in connection with whatare considered the most practical and preferred embodiments, it isunderstood that this invention is not limited to the disclosedembodiments but is intended to cover various arrangements includedwithin the spirit and scope of the broadest interpretation so as toencompass all such modifications and equivalent arrangements.

What is claimed is:
 1. An imaging lens comprising, a first lens element,a second lens element, a third lens element, a fourth lens element, afifth lens element and a sixth lens element arranged in order from anobject side to an image side along an optical axis of said imaging lens,each of said first lens element, said second lens element, said thirdlens element, said fourth lens element, said fifth lens element and saidsixth lens element having a refractive power, an object-side surfacefacing toward the object side, and an image-side surface facing towardthe image side, wherein: said first lens element has a negativerefractive power, said object-side surface of said first lens element isa convex surface that has a convex portion in a vicinity of the opticalaxis and a convex portion in a vicinity of a periphery of said firstlens element; said image-side surface of said second lens element has aconvex portion in a vicinity of a periphery of said second lens element;said third lens element has a positive refractive power and saidimage-side surface of said third lens element has a convex portion in avicinity of a periphery of said third lens element; said object-sidesurface of said fourth lens element has a concave portion in a vicinityof a periphery of said fourth lens element; said object-side surface ofsaid fifth lens element has a concave portion in a vicinity of aperiphery of said fifth lens element, said image-side surface of saidfifth lens element has a concave portion in a vicinity of the opticalaxis; said image-side surface of said sixth lens element has a concaveportion in a vicinity of the optical axis and a convex portion in avicinity of a periphery of said sixth lens element; said imaging lensdoes not include any lens element with refractive power other than saidfirst lens element, said second lens element, said third lens element,said fourth lens element, said fifth lens element and said sixth lenselement; and said imaging lens further satisfying T3/T4≧1.7, where T3represents a thickness of said third lens element at the optical axisand T4 represents a thickness of said fourth lens element at the opticalaxis.
 2. The imaging lens as claimed in claim 1, satisfying Gaa/T5≧1.25,where Gaa represents a sum of air gap widths among said first lenselement, said second lens element, said third lens element, said fourthlens element, said fifth lens element and said sixth lens element at theoptical axis, and T5 represents a thickness of said fifth lens elementat the optical axis.
 3. The imaging lens as claimed in claim 2, furthersatisfying T6/T1≦2.6, where T1 represents a thickness of said first lenselement at the optical axis and T6 represents a thickness of said sixthlens element at the optical axis.
 4. The imaging lens as claimed inclaim 2, further satisfying (G34+G56)/G12≦5.0, where G12 represents anair gap width between said first lens element and said second lenselement at the optical axis, G34 represents an air gap width betweensaid third lens element and said fourth lens element at the opticalaxis, and G56 represents an air gap width between said fifth lenselement and said sixth lens element at the optical axis.
 5. The imaginglens as claimed in claim 1, satisfying T6/T3≦1.5, where T6 represents athickness of said sixth lens element at the optical axis.
 6. The imaginglens as claimed in claim 5, further satisfying ALT/T5≧5.0, where ALTrepresents a sum of thicknesses of said first lens element, said secondlens element, said third lens element, said fourth lens element, saidfifth lens element and said sixth lens element at the optical axis, andT5 represents a thickness of said fifth lens element at the opticalaxis.
 7. The imaging lens as claimed in claim 1, satisfying ALT/G12≦30,where ALT represents a sum of thicknesses of said first lens element,said second lens element, said third lens element, said fourth lenselement, said fifth lens element and said sixth lens element at theoptical axis, and G12 represents an air gap width between said firstlens element and said second lens element at the optical axis, and saidimage-side surface of said fifth lens element has a concave portion in avicinity of the optical axis.
 8. The imaging lens as claimed in claim 7,further satisfying (G23+G34)/T4≦1.5, where G23 represents an air gapwidth between said second lens element and said third lens element atthe optical axis, G34 represents an air gap width between said thirdlens element and said fourth lens element at the optical axis.
 9. Theimaging lens as claimed in claim 7, further satisfying T2/(G45+G56)≦3.0,where G45 represents an air gap width between said fourth lens elementand said fifth lens element at the optical axis, G56 represents an airgap width between said fifth lens element and said sixth lens element atthe optical axis, and T2 represents a thickness of said second lenselement at the optical axis.
 10. The imaging lens as claimed in claim 1,satisfying T6/G12≦7.0, where T6 represents a thickness of said sixthlens element at the optical axis and G12 represents an air gap widthbetween said first lens element and said second lens element at theoptical axis.
 11. The imaging lens as claimed in claim 10, furthersatisfying T5/T1≦2.1, where T1 represents a thickness of said first lenselement at the optical axis and T5 represents a thickness of said fifthlens element at the optical axis.
 12. The imaging lens as claimed inclaim 10, further satisfying Gaa/(G23+G34)≧2.0, where Gaa represents asum of air gap widths among said first lens element, said second lenselement, said third lens element, said fourth lens element, said fifthlens element and said sixth lens element at the optical axis, G23represents an air gap width between said second lens element and saidthird lens element at the optical axis, and G34 represents an air gapwidth between said third lens element and said fourth lens element atthe optical axis.
 13. The imaging lens as claimed in claim 1, satisfying(G23+G34)/G12≦4.8, where G12 represents an air gap width between saidfirst lens element and said second lens element at the optical axis, G23represents an air gap width between said second lens element and saidthird lens element at the optical axis, and G34 represents an air gapwidth between said third lens element and said fourth lens element atthe optical axis.
 14. The imaging lens as claimed in claim 13, furthersatisfying T5/(G45+G56)≦2.7, where T5 represents a thickness of saidfifth lens element at the optical axis, G45 represents an air gap widthbetween said fourth lens element and said fifth lens element at theoptical axis, and G56 represents an air gap width between said fifthlens element and said sixth lens element at the optical axis.
 15. Theimaging lens as claimed in claim 13, further satisfying T5/T3≦1.05,where—T5 represents a thickness of said fifth lens element at theoptical axis.
 16. An electronic apparatus comprising: a housing; and animaging module disposed in said housing, and including an imaging lensas claimed in claim 1, a barrel on which said imaging lens is disposed,a holder unit on which said barrel is disposed, and an image sensordisposed at the image side of said imaging lens.
 17. The imaging lens asclaimed in claim 1, wherein said object-side surface of said third lenselement has a convex portion in a vicinity of a periphery of said thirdlens element.
 18. The imaging lens as claimed in claim 1, wherein saidimage-side surface of said fourth lens element has a concave portion ina vicinity of the optical axis.